a.jpegThe Os Trigonum: Small Bone, Big Problem

In ballet, extreme plantarflexion, demi‑pointe and full pointe, places immense repetitive stress on the posterior ankle. Up to one-third of dancers have an os trigonum, an accessory bone located just behind the talus. Normally silent, this bone becomes “nut‑crushed”, between the tibia and calcaneus during intense plantarflexion, initiating posterior ankle impingement syndrome (Nutcracker Syndrome). Dancers typically describe deep posterior ankle pain, sharp pinching, or a dull ache during and after pointe work. Many times, dancer’s present to me with complaints of Achilles tendon pain or tendinitis.  But here’s the thing, the Achilles doesn’t typically hurt with passive plantarflexion of the ankle.  Posterior impingement pain causes a chandelier sign with passive flexion (jump to the chandelier!)

Advanced imaging often reveals not only the os trigonum but also concurrent inflammation of the flexor hallucis longus (FHL) tendon—there’s a natural anatomical relationship between the two.  At Prisk Orthopaedics, we find this relationship easily with a combination of ultrasound and the LineUp CT scanner.  

FHL Tendon Strain: More Than Just Tendonitis

The FHL is the powerhouse behind big‑toe flexion and arch stability, winding under the ankle and wrapping around the sustentaculum tali. These repetitive, high-stress motions—rises, relevés, toe-offs, can subject the tendon to forces up to ten times body weight. Over time, this results in inflammation, triggering, and narrowing of the FHL sheath, colloquially known as “dancer’s tendonitis.”

When an os trigonum is present, the tendon gets squeezed even more during the extreme motions of ballet, compounding irritation and causing simultaneous FHL tenosynovitis and posterior impingement. Common signs include posteromedial ankle pain, painful passive or active toe movements, and possible triggering of the big toe.

Loose Ankles & Kinetic Chain Dysfunction: An Overlooked Culprit

Dancers often exhibit increased ligamentous laxity and subtle lateral ankle instability. This leads to abnormal ankle rotations and frontal-plane motion, worsening bone contact in the posterior ankle during plantarflexion. Instability increases the likelihood of impingement and worsens FHL strain.

Beyond the ankle, the entire kinetic chain plays a pivotal role. Weak gluteal muscles or restricted hip internal rotation force dancers to compensate further down, often through excessive foot pronation during first and fifth positions and with plie.  This biomechanical overload directs undue stress onto the FHL. Improved hip ROM and gluteal strength are vital to breaking this compensatory chain and unloading the posterior ankle complex.


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Conservative Care:

Step One

Initial management always begins with conservative care. This involves:

  • Relative-Rest and activity modifications like limiting releve and marking dance choreography. 
  • Anti-inflammatories and ice, iontophoresis in physical therapy
  • Physical therapy focused on dorsiflexion, glute/hip strengthening, and ankle proprioception
  • Temporary immobilization or support
  • Occasionally, corticosteroid injections to quiet acute inflammation in the posterior ankle.  In fact, especially when an os trigonum is not present, a steroid injection can be curative. 
  • Manual therapy and corrective movement training targeting the kinetic chain

While these measures are effective for many (up to 60%), persistent impingement, especially when an os trigonum or significant FHL disease is present, often requires more definitive intervention.

My Signature Posterior Endoscopic Surgery

At Prisk Orthopaedics & Wellness, I’m proud to be one of the only, if not THE only physician in Pittsburgh performing posterior endoscopic (arthroscopic) os trigonum excision combined with FHL tenolysis and/or repair.  Using small posteromedial and posterolateral portals and a 2.4 mm arthroscope, this minimally invasive technique allows me to precisely remove the bony impinger and treat tendon pathology with exceptional visualization.

Major advantages of Hindfoot Endoscopy:

  • Smaller incisions and less scar tissue compared to open surgery
  • Direct treatment of both os trigonum and FHL issues in one procedure
  • Lower complication risk; faster recovery

Clinical outcomes are outstanding: most ballet dancers resume demi‑pointe by week 4 and full pointe by week 6 post-op. Athletic patients respond greatly as well and even return quicker. Results speak volumes: pain resolves, function returns, and dancers are back in full choreography, usually within six weeks. (your results may vary depending on your unique condition)

A Seamless Recovery Plan

In my hands, recovery is structured, progressive, and dance-specific:

  • Weeks 0–2: Full weight-bearing in a boot; initiation of ankle range-of-motion exercises. Core, glute, and hip activation begin early in rehab.
  • Weeks 2–4: Full weight-bearing; joint mobilization; proprioceptive work; targeted hip and ankle strengthening; low-impact conditioning.
  • Weeks 5–6: Controlled return to demi‑pointe; monitored pointe technique under a physical therapist’s guidance.
  • Weeks 6–10: Full reintegration into dance, including jumps and choreography; ongoing kinetic chain conditioning to prevent recurrence.

The combination of surgical precision and rigorous attention to hip/glute/ankle mechanics ensures strong, sustainable results.

Why My Approach Is Unique

Specialty training in posterior ankle endoscopic surgery: a rare and advanced expertise in this region.

Focused dual treatment: remove the os trigonum and address FHL tendon irritation in a single operation.

Holistic kinetic chain assessment: I evaluate and correct hip mobility, glute function, and ankle stability before and after surgery.

Evidence-based rehab protocol: drawing from ballet-specific rehab literature to guide safe, accelerated return.

Consistent staging for dance readiness: ceremonial demi‑pointe by week 4, followed by full pointe by week 6, supported by clinical evaluation.

Final Thoughts

Posterior ankle impingement in dancers often arises from a perfect storm: os trigonum, FHL irritation, ankle instability, and proximal kinetic chain dysfunction. Ballet’s artistic demands compound these factors.

As Pittsburgh’s premier surgeon utilizing posterior endoscopic excision with FHL tenolysis, I deliver a tailored, minimally invasive one‑two approach, treating both bone and tendon issues while reinforcing the kinetic chain. My targeted recovery pathway ensures dancers are back en pointe in 4–6 weeks, with optimized strength, technique, and biomechanics.

If posterior ankle pain is holding you back, let’s evaluate your kinetic chain, imaging, and options. Together, we can correct pathology, rebuild function, and reclaim your artistry—stronger, more stable, and pain‑free.
Please give me a call at 412-525-7692 to make an appointment today.